Method and a video game system of generating a field map

ABSTRACT

A method and a video game system that are capable of generating a field map with more natural geographical feature. The method and the video game system firstly divides the field map including a plurality of blocks into a first zone and a second zone by a boundary which consists of sides and comers in the blocks, then determines a first point for each side included in the boundary and a second point for each corner included in the boundary. Finally, the boundary is transformed into a more complex land shape by connecting the first points and the second points. The video game system includes a block division unit that divides the field map into a plurality of blocks, a block assign unit that assigns each of the divided blocks to either a first zone or a second zone using a boundary that consists of sides and comers of the blocks, a first point determining unit that determines a first point for each side, a second point determining unit that determines a second point for each corner, and a transforming unit that transforms the boundary by connecting the first points and the second points.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates to a method of generating a field mapautomatically in a video game, and in particular, a method of generatingmore natural geographical features by transforming a selectedquadrilateral automatically.

2. Description of the Related Art

In recent years, video game devices have spread to many familiesquickly. And there are various types of game, such as a role-playinggame, a simulation game, a combat game, a puzzle game, and the like.

In a typical role-playing game, dungeon is often used. In the game,treasure or items which are necessary for the game may be hidden in thedungeon, or a strong monster may appear from the dungeon.

Herein, the dungeon generally means “labyrinth” in an actual game.Therefore, the dungeon may be expressed as land, a natural cave, an icecave, or a lava cave. In such a game, a video game character (forexample, main character) moves in the dungeon and therein, encountersvarious items and monsters, as a story of the game proceeds. Of course,the story varies according to selection of loads or response toencountering of the items or monsters. In this specification, image datarepresenting whole geographical features which are used as the dungeonare referred to as a “field map”.

In general, it is necessary to prepare many patterns of shapes of thedungeon (for example, shapes of land) so that a user of the game doesnot lose interest in the game. To this end, when the game is started orat the other timing, a shape of the dungeon is automatically generated,for example, by using a random number.

However, in the prior game, a shape of the dungeon which isautomatically generated becomes unnatural shape since the dungeon isgenerated by combining a plurality of quadrilaterals. For example, evenif the dungeon expresses land or a cave, a boundary of the dungeon, thatis, a boundary line between the land and the sea surrounding the dungeonis not generated in a natural and complex shape.

In other words, the boundary line is formed as a shape of steps, thatis, a shape with coarse notches in the prior game. Due to the limitationof expression, natural and complex geographical features are not fullyrepresented. Therefore, when a story of the game proceeds on a nature,it is not possible to communicate to a user of the game a feeling ofopen-air or refreshment, as a result, it is not possible to give theuser a feeling of being at a live performance.

SUMMARY OF THE INVENTION

It is therefore an object of the invention to provide a method ofrepresenting dungeon in more natural shape. To this end, the methodtransforms a part of field map representing the dungeon to generate morenatural shape of dungeon.

According to a first aspect of the invention, there is provided a methodof generating a field map used in a video game. The method comprisessteps of dividing the field map which consists of a plurality of blocks,into a first zone and a second zone by a boundary including sides andcorners, determining a first point for each side of the boundary on thebasis of a location of each side of the boundary, determining a secondpoint for each corner of the boundary on the basis of a location of eachcorner of the boundary, and transforming the boundary by connecting thefirst points and the second points.

According to a second aspect of the invention, there is provided amethod of generating a field map used in a video game. The methodcomprises steps of dividing the field map into a plurality ofquadrilateral blocks, assigning each of the divided blocks to either afirst zone or a second zone, selecting sides each of which forms a partof a boundary between the first zone and the second zone, from sides ofthe blocks, selecting a point which corresponds to a corner of one ofthe blocks and which is included in the boundary, determining a firstpoint for each selected side on the basis of a location of each side ofthe boundary, determining a second point for each selected point on thebasis of a location of each corner of the boundary, and transforming theboundary by connecting the first points and the second points.

According to a third aspect of the invention, there is provided a methodof generating a field map used in a video game. The method comprisessteps of dividing the field map into a plurality of quadrilateral cells,assigning each of the divided cells to either a first zone or a secondzone, determining a first cell which belongs to the first zone and isnext to a cell which belongs to the second zone, selecting a cell whichbelongs to the first zone and is next to the first cell, and furtherrepeatedly selecting a cell which belongs to the first zone and is nextto the selected cell, and transforming a boundary between the first zoneand the second zone by changing cells having a predetermined locationrelationship to the selected cells to cells which belong to the secondzone.

According to a fourth aspect of the invention, there is provided amethod of generating a field map used in a video game. The methodcomprises steps of dividing the field map into a plurality ofquadrilateral blocks including a plurality of quadrilateral cells,assigning each of the divided blocks to either a first zone or a secondzone, selecting sides each of which forms a part of a boundary betweenthe first zone and the second zone, from sides of the blocks, selectinga point which corresponds to a corner of one of the blocks and which isincluded in the boundary, determining a first point for each selectedside on the basis of a location of each side of the boundary,determining a second point for each selected point on the basis of alocation of each corner of the boundary, selecting two first points eachof which corresponds to a side, the two corresponding sides are adjacentto each other, selecting one second point which corresponds to a cornerformed by the two corresponding side, determining a third point bymoving the selected second point on the basis of an aspect of theassigning of the divided blocks to the first zone or the second zone,transforming the boundary by connecting the two selected first pointsand a point which is optionally selected from the selected second pointand the determined third point, selecting a first cell which belongs tothe first zone and is next to a cell which belongs to the second zone,selecting a cell which belongs to the first zone and is next to thefirst cell, further selecting a cell which belongs to the first zone andis next to the selected cell, and repeating the selection of a cell, andtransforming the transformed boundary by changing cells having apredetermined location relationship to the selected cells to cells whichbelong to the second zone.

According to a fifth aspect of the invention, there is provided a videogame system which generates a field map. The system comprises blockdivision means which divides the field map into a plurality ofquadrilateral blocks, block assign means which assigns each of thedivided blocks to either a first zone or a second zone, side selectmeans which selects sides each of which forms a part of a boundarybetween the first zone and the second zone, from sides of the blocks,corner select means which selects a point which corresponds to a comerof one of the blocks and which is included in the boundary, first pointdetermining means which determines a first point for each selected sideon the basis of a location of each side of the boundary, second pointdetermining means which determines a second point for each selectedpoint on the basis of a location of each corner of the boundary, andfirst transforming means which transforms the boundary by connecting thefirst points and the second points.

According to a sixth aspect of the invention, there is provided a videogame system which generates a field map. The system comprises celldividing means which divides the field map into a plurality ofquadrilateral cells, cell assign means which assigns each of the dividedcells to either a first zone or a second zone, first cell selectingmeans which selects a first cell which belongs to the first zone and isnext to a cell which belongs to the second zone, second cell selectingmeans which selects a cell which belongs to the first zone and is nextto the first cell, further selecting a cell which belongs to the firstzone and is next to the selected cell, and repeating the selection of acell, and transforming means which transforms a boundary between thefirst zone and the second zone by changing cells having a predeterminedlocation relationship to the selected cells to cells which belong to thesecond zone.

According to a seventh aspect of the invention, there is provided avideo game system which generates a field map. The system comprisesblock division means which divides the field map into a plurality ofquadrilateral blocks including a plurality of quadrilateral cells, blockassign means which assigns each of the divided blocks to either a firstzone or a second zone, side select means which selects sides each ofwhich forms a part of a boundary between the first zone and the secondzone, from sides of the blocks, corner select means which selects apoint which corresponds to a corner of one of the blocks and which isincluded in the boundary, first point determining means which determinesa first point for each selected side on the basis of a location of eachside of the boundary, second point determining means which determines asecond point for each selected point on the basis of a location of eachcorner of the boundary, first point selecting means which selects twofirst points each of which corresponds to a side, the two correspondingsides are adjacent to each other, second point selecting means whichselects one second point which corresponds to a corner formed by the twocorresponding side, third point determining means which determines athird point by moving the selected second point on the basis of anaspect of the assigning of the divided blocks to the first zone or thesecond zone, first transforming means which transforms the boundary byconnecting the two selected first points and a point which is optionallyselected from the selected second point and the determined third point,first cell selecting means which selects a first cell which belongs tothe first zone and is next to a cell which belongs to the second zone,second cell selecting means which selects a cell which belongs to thefirst zone and is next to the first cell, and repeating the selection ofa cell, and second transforming means which transforms the transformedboundary by changing cells having a predetermined location relationshipto the selected cells to cells which belong to the second zone.

According to an eighth aspect of the invention, there is provided arecording medium readable by a computer, tangibly embodying a program ofgenerating a field map used in a video game. The program comprises stepsof dividing the field map into a plurality of quadrilateral blocks,assigning each of the divided blocks to either a first zone or a secondzone, selecting sides each of which forms a part of a boundary betweenthe first zone and the second zone, from sides of the blocks, selectinga point which corresponds to a corner of one of the blocks and which isincluded in the boundary, determining a first point for each selectedside on the basis of a location of each side of the boundary,determining a second point for each selected point on the basis of alocation of each corner of the boundary, and transforming the boundaryby connecting the first points and the second points.

According to a ninth aspect of the invention, there is provided arecording medium readable by a computer, tangibly embodying a program ofgenerating a field map used in a video game. The program comprises stepsof dividing the field map into a plurality of quadrilateral cells,assigning each of the divided cells to either a first zone or a secondzone, selecting a first cell which belongs to the first zone and is nextto a cell which belongs to the second zone, selecting a cell whichbelongs to the first zone and is next to the first cell, furtherselecting a cell which belongs to the first zone and is next to theselected cell, and repeating the selection of a cell, and transforming aboundary between the first zone and the second zone by changing cellshaving a predetermined location relationship to the selected cells tocells which belong to the second zone.

According to a tenth aspect of the invention, there is provided arecording medium readable by a computer, tangibly embodying a program ofgenerating a field map used in a video game. The program comprises stepsof dividing the field map into a plurality of quadrilateral blocksincluding a plurality of quadrilateral cells, assigning each of thedivided blocks to either a first zone or a second zone, selecting sideseach of which forms a part of a boundary between the first zone and thesecond zone, from sides of the blocks, selecting a point whichcorresponds to a corner of one of the blocks and which is included inthe boundary, determining a first point for each selected side on thebasis of a location of each side of the boundary, determining a secondpoint for each selected point on the basis of a location of each cornerof the boundary, selecting two first points each of which corresponds toa side, the two corresponding sides are adjacent to each other,selecting one second point which corresponds to a corner formed by thetwo corresponding side, determining a third point by moving the selectedsecond point on the basis of an aspect of the assigning of the dividedblocks to the first zone or the second zone, transforming the boundaryby connecting the two selected first points and a point which isoptionally selected from the selected second point and the determinedthird point, selecting a first cell which belongs to the first zone andis next to a cell which belongs to the second zone, selecting a cellwhich belongs to the first zone and is next to the first cell, furtherselecting a cell which belongs to the first zone and is next to theselected cell, and repeating the selection of a cell, and transformingthe transformed boundary by changing cells having a predeterminedlocation relationship to the selected cells to cells which belong to thesecond zone.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a block diagram of a video game device according to anembodiment of the invention;

FIG. 2 shows a flowchart representing a method according to anembodiment of the invention;

FIG. 3 shows field map, including eight by eight blocks, in which anarea is selected;

FIGS. 4A and 4B show diagrams schematically representing a firsttransforming process;

FIG. 5 shows a diagram representing a part of the field map which isdivided into 128 by 128 cells;

FIG. 6 shows a diagram of field map which is processed by the firsttransforming process;

FIG. 7 shows a diagram of field map after a path is added to the fieldmap of FIG. 6;

FIGS. 8A-8E show diagrams representing child blocks each of whichstretches over four blocks;

FIGS. 9A-9D show diagrams representing child blocks each of whichstretches over two blocks;

FIGS. 10A and 10B show diagrams representing patterns of extensionprocess;

FIGS. 11A and 11B show diagrams representing other patterns of extensionprocess;

FIGS. 12A and 12B show diagrams representing procedure of wearingprocess; and

FIG. 13 shows an example of finally obtained field map.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring to FIG. 1, description is at first made about a video gamedevice of an embodiment of the invention. The video game device shown inFIG. 1 is merely exemplified and may be changed to any other gamedevices or machines.

The video game device 100 shown in FIG. 1 includes a body 100, atelevision monitor 130, a speaker 140, a recording medium 150, a memorycard 160, and a controller 170. The elements 130 through 170 areconnected to the body 100. The game device is suited for home use.

The body 100 further includes a CPU 111, a bus 112 connected to the CPU111, and some elements connected to the bus 112.

The bus 112 includes an address bus, a data bus, and a control bus. Agraphic data generating processor 113, a peripheral device controller114, a main memory 115, a ROM 116, an expansion circuit 117, a graphicprocessor 118, a frame buffer 119, a sound processor 120, a sound buffer121, a decoder 123, a buffer 122, a recording medium drive 124, and aninterface circuit 125.

The television monitor 130 (hereinafter, referred to as a “monitor”) isconnected to the graphic processor 118. Further, the speaker 140 isconnected to the sound processor 120, and the memory card 160 and thecontroller 170 are connected to the interface circuit 125.

As mentioned above, the video game device shown in FIG. 1 is an examplesuited for home use. In this case, it is general that the monitor of ahome television is used as the monitor 130 and a speaker of the hometelevision is used as the speaker 140.

In the case where the method according to the invention is applied tothe arcade game device, the above mentioned elements shown in FIG. 1 maybe all incorporated into a single body.

Also, when the method of the invention is used in a personal computer ofa workstation, a CRT display connected to the personal computer may beused as the monitor 10, and an input device such as a keyboard or amouse is used as the controller 20.

Then, description is made about the game device in more detail.

The CPU 111 is, for example, a 32-bits RISC (reduced instruction setcomputer), and controls all elements of the game device by executing anoperating system program stored in a ROM 116, which is described later.

The graphic data generating processor 113 serves as a co-processor ofthe CPU 111. That is, the processor 113 executes calculation forcoordinate transformation and a light source, for example, operation offixed decimal or vector, with parallel processing to display a pseudothree-dimensional image.

The peripheral device controller 114 executes control operation forinterruption, time, memory, and direct memory access (DMA) transfer. TheROM 116 stores, as described above, the operating system program whichcontrols operations of the elements in the game device.

The expansion circuit 117 decodes still or animated image data read outfrom the recording medium 150 and stored in the main memory 115, underthe control of the aforementioned CPU 111, and stores the decoded imagedata back in the main memory 115. Specifically, the expansion circuit117 is capable of carrying out high-speed execution of inverse discretecosine transform (inverse DCT) operations, and it is also capable ofexpanding compressed data read out from the recording medium 150 inaccordance with still color image compression standards (known as JPEG)or cumulative media moving image encoding standards (known as MPEG).

Field map is generated according to the method of transforming field mapof the invention, and the field map is stored into the frame buffer 119.Consequently, the field map is displayed on the monitor 130. The aboveprocess is cooperatively executed by the CPU 111, the graphic datagenerating processor 113, the graphic processor 118, and the framebuffer 119. Description about the process will be made later in moredetail.

The frame buffer 119 includes a display area and a non-display area. Thedisplay area is an area for storing images corresponding to a displayarea on the monitor 130. The non-display area is an area for storinganimation images used to produce two-dimensional images in the displayarea and textures used to produce pseudo three-dimensional images.

In some case, the frame buffer 119 includes a color lookup table (CLUT)which corresponds to a color of pixel to a number. Also, data in thedisplay area in the frame buffer 119 are transferred to the monitor 130at high-speed. The frame buffer 119 consists of a so-called dual-portRAM, and it is capable of simultaneously receiving images from thegraphic data generating processor 113 (CPU 111 ) or transferring datafrom the main memory 115, and reading out data in order that the datacan be displayed to the monitor 130.

The sound processor 120 outputs music or an effective sound via speaker140 by regenerating ADPCM data in the recording medium 150 or voice datastored in the sound buffer 121, or by modulating and regenerating thevoice data.

The decoder 123 decodes a program or data which are stored in therecording medium 150 and are appended an error correction code (ECC),and provides the program or the data to the main memory 115 or the soundprocessor 120.

The buffer 122 temporarily stores the program and/or data regeneratedfrom the recording medium 150. The buffer 122 has a memory capacity of,for example, 32 kilobytes.

The recording medium drive 124 may be a CD-ROM drive, an optical diskdrive, or the like. The recording medium drive 124 reads a program andanother data out of the recording medium 150, and provides them to thedecoder 123.

The interface circuit 125 sends an operation signal received from thecontroller 170 to the CPU 111. Also, the interface circuit 125 reads outthe contents of the memory card 160 to supply the contents to the mainmemory 115, and simultaneously stores data into the memory card 160 inresponse to an instruction of the CPU 111.

A recording medium 150 stores a program and image data required to playa game. The program and the image data are read from the recordingmedium 150 to a video game device via the recording medium drive 124.The recording medium itself is, for example, a CD-ROM or an opticaldisk.

The memory card 160 stores values of a various of parameters in orderto, for example, maintain the status at the time point when a gameterminates last time. The values are transferred to the memory card 160via the interface circuit 125 as required. To this end, the memory card160 is connected to a slot of the interface circuit 125.

A handy-type video game device is also connected to a slot of the frontside of the interface circuit 125, and a program and data of the videogame of the body 100, required to play a game are transferred to thehandy-type video game device.

The controller 170 is manipulated to play a game by a user. Thecontroller 170 includes direction buttons for moving a character on themonitor upwards, downwards, leftwards and rightwards, and a plurality offunction buttons for instructing one of specific functions, for example,starting the game or selecting items.

The method of transforming field map of the invention may be used in,for example, the following RPG game.

In the RPG game, four partial scenarios are selected from a firstpartial scenario through a tenth partial scenario, and the selectedpartial scenarios are combined as a first stage through a fourth stageto generate a story of the game.

According to a condition of ending of the first stage partial scenario,the second stage partial scenario is dynamically selected. Herein, thecondition of ending of the first stage partial scenario and a conditionof starting of the second stage partial scenario are related so that atransition of two partial scenario is naturally done as a story.

Specifically, the first stage partial scenario is selected from thefirst partial scenario through the eighth partial scenario, and thecondition of ending of the first stage partial scenario is preparedaccording to a result of processing in the scenario. Therefore, one ofthe first partial scenario through the tenth partial scenario may beselected as the second stage partial scenario. Thereafter, similarselections are done about the third stage partial scenario and thefourth stage partial scenario.

In the RPG game, scene (area) is changed for each partial scenario,thereby a user of the game newly interests in the game. For example, afirst island, a second island, a third island, and a fourth island (afirst area through a fourth area) which are defined on a field mapcorresponds to the first stage partial scenario, the second stagepartial scenario, the third stage partial scenario, and the fourth stagepartial scenario, respectively, and at the end of the first stagepartial scenario, a scene displaying the first island is changed toanother scene displaying the second island.

The change of the scene is a part of the game (story), for example, ifthe condition of ending of the first stage partial scenario is meet, thesecond island is displayed, and a bridge is created or a ferry isprovided so that the main character may move from the first island tothe second island.

As described above, the appearance and the change of these scene areimportant element for the game. Therefore, if the scene (area) includesnatural geographical features, such as islands or land, naturalexpression of the scene (area) is required so that the user may feelopen-air or refreshment sense, and atmosphere of being at a liveperformance.

Next, description is made about transform process of a field mapaccording to the invention with reference to FIGS. 2 through 13.

In FIG. 2, a flowchart of the transform process is shown. At step S10,the field map is divided into 64 (8 by 8) quadrilateral blocks. Thisdivided field map is shown in FIG. 3. Herein, for designating each blocklater, each column of the divided field map is related to one ofnumerals 1 to 8, and each row of the divided field map is related to oneof characters A to H. Thereby, a block in the field map is specified byusing one of the numerals and one of the characters. For example, theblock located at the top right of the field map is referred to as block(8A).

At step S12, four areas to which land is assigned are selected. Eacharea includes at least five blocks, since an area composed of less thanfive blocks is not enough to express land in the present game. But, anarea may include any number of blocks.

In this example, each area corresponds to one of the above mentionedfour partial scenarios and the dungeon is formed as land. The concept ofthe invention may be applied similarly when the other dungeon patternsare used.

The selection of the areas are generally done by using a random number.But, the areas may also decided based on factors such as a valuedesignated by the user or outside information. Hereinafter, when processuses the random number (or process is randomly performed) in thespecification, it is implicitly shown that there is a possibility that aresult which is different from the previously given result is obtainedwhen the process is repeated such as by restarting the game or moving tothe other scenario.

For example, when the game is restarted, other four areas formsdifferent shape of land.

Also, the number of blocks of the whole areas or the number of the areamay be limited according to characteristics of game. Herein, theunselected areas represent the sea.

Thereafter, the selected areas are each divided into two sub areas atstep S14. Thereby, in addition to boundaries among the four areas,boundaries between the above two sub areas are generated. According tothe invention, more natural geographical features may be generated bylocating a mountain or a river along the boundaries of the sub areas.

Further, at step S16, some blocks may be selected as additional subareas from the remaining blocks which are not selected as the four areasand are next to one of the blocks selected as the four area. Herein,three additional sub areas may be added and each sub area includes oneblock. The additional sub areas are also generated to realize naturalgeographical features.

Thus selected areas are also shown in FIG. 3. The areas selected at stepS12 are an area a (a0 and a1), an area b (b0 and b1), an area c (c0 andc1), and an area d (d0 and d1). Herein, the blocks in each parenthesisare sub areas divided at step S14. The additional areas added at stepS16 are a2, a3, and c2. Consequently, the field map of FIG. 3 includesthe area a (a0, a1, a2, and a3), the area b (b0 and b1), the area c (c0,c1, and c2), the area d (d0 and d1).

Next, at step S18, definition is made and appearance of land at each subarea is determined. In this example, two sub areas are defined so as toinclude a snowy field, other two areas are defined so as to include adesert, and the other areas are defined so as to include a grassy plain.These definitions are generally generated by using a random number, butas described above, the other way may be used. Specifically, the subareas b0 and b1 includes the snowy field and the sub areas c0 and c2includes the desert.

Then, for each selected block, five points are given at step S20. Thesepoints are places where a town, a harbor, a cave, or a tower arelocated.

Description is made about the establishment of the points with referenceto FIGS. 4 and 5.

In FIG. 4A, three blocks (5A, 5B, and 6B) are shown. On the other hand,FIG. 5 shows enlarged blocks near the block 5B in the field map of FIG.3 and the field map is divided into 128 by 128 cells.

In FIG. 3, one quadrilateral corresponds to one block, but in FIG. 5, 16by 16 cells (quadrilaterals) correspond to one block. Herein, eachquadrilateral formed by dividing the field map into 128 by 128 isreferred to as “cell”. The cell corresponds to pixel of the image on amonitor. Color is defined for each cell, as a whole, an image isdisplayed on the monitor.

Referring to FIG. 4A again, points “1” are each located at the center ofthe blocks (denoted by symbols “”) and points “2” are each located nearthe midpoint of one of the four sides of the blocks (denoted by symbols“”).

Each point “1” is located at the center of the block, but it is notnecessary that the center strictly means the center of gravity.Therefore, the point “1” is located at a location which is determined ina predetermined range near the center by using such as a random number.The predetermined range is, for example, shown as 5A′ in FIG. 5 which is8 by 8 cells located at a central portion of the block and denoted as ashaded portion. Hereinafter, the size of cells is referred to as “subblock”.

On the other hand, the point “2” is located for each side of each block,but it is not necessary to locate the midpoint of the side. A locationof the point “2” may be determined in a predetermined range near themidpoint by using such as a random number. The range is shown as a subblock Q3 in FIG. 5, which includes boundaries between blocks.

Four points “2” are given for each block, but when there are blockssharing a side with the other block, the point “2” is also shared. Forexample, in FIG. 4A, the block 6B and the block 5B share a point “2”,and the block 5A and block 5B share a point “2”.

Next, at step S22, transformation process is performed using the points“2”. Referring to FIG. 4A, at first, middle additional point is givenbetween two points “2” which located at adjacent exterior sides of theblocks forming an area (that is, the seaside). In FIG. 4A, in additionto the points “1” and the points “2”, the middle additional points areshown (P1 to P4, denoted by symbol “▴”. The middle additional points arelocated in a predetermined range by using a random number. Thepredetermined range is, for example for the middle additional point P2,a sub block Q2 shown in FIG. 5 which covers blocks 5A, 6A, 5B, and 6Band is composed of 8 by 8 cells surrounded by shaded frame. Similarly,the middle additional point P1 is located in a sub block Q1. However,the point P1 is not located at a portion above the row A, since theportion is out of the field map. Therefore, a location of the P1 isdetermined in a portion where the row A and the sub block Ql overlapeach other by using a random number. Similarly, middle additional pointsP3 and P4 are determined, as a result, outline of land shown in FIG. 4B(denoted by a bold line) is obtained.

By moving each apex of the area in a predetermined range, it is possibleto change the prior unnatural boundary line which is formed as a shapeof steps to more natural boundary line, to express more complex seaside.Further, the transformed boundary line is transformed so as to express ashape closer to a natural shape. This second transformation is describedlater in more detail.

Referring to flowchart of FIG. 2 again, in step S24, reads are locatedbetween the points. The process locate a crossroads by connecting thetop point “2” and the bottom point “2” passing through the point “1”,and connecting the right point “2” and the left point “2” passingthrough the point “1”. In FIG. 7, the field map including thus locatedcrossroads is shown. It is not necessary that each road is formed as astraight line, and as a shape of the road, any shape including a curvemay be selected based on, for example, a random number. Each of theroads is assigned as a path where the character of the game walksthrough, but the road is not always displayed as a path. The road issometime displayed, as if the road does not exist, for example, as agrass field or a forest. Also, step S24 may be performed after step S20or before step S28 described later. For each cell, information whetheror not the cell is assigned as the road is retained.

Next, in step S26, the second transformation is performed. The processextends or wears away the field map which is transformed at step S22(the first transformation).

Description is made about the second transformation with reference tothe sub blocks shown in FIG. 5. The sub block includes 8 by 8 cells andmay be categorized into the following three categories (1) to (3).

(1) Sub block located at the center of a block (5A′ in FIG. 5).

(2) Sub block located to cover four blocks (Q1 and Q2 in FIG. 5).

(3) Sub block located to cover two blocks (Q3 in FIG. 5).

Sub block of categories (2) and (3) is further categorized based onwhether the surrounding blocks are land or the sea. The categorizationis explained with reference to FIGS. 8A to 8E and 9A to 9D. Herein,quadrilateral which is denoted by bold line and covers two or fourblocks is subjective sub block. Name of the sub block is shown inbetween “[” and “]”, for example “[SEA]”.

Next, description is made about the further categorization of thecategory (2). The category (2) is still categorized into categories(2-1) to (2-5). (2-1) At least one of the surrounding blocks is the seaand the rest are land of the same area ([SEA_SAME]). The sub block ofthe case is shown in FIG. 8A. At most, three sea blocks may exist.

(2-2) At least one of the surrounding blocks is the sea and the rest areland ([SEA_DIFFER]). Further, land of one of the land blocks belongs todifferent area of land of another land block. The sub block of the caseis shown in FIG. 8B. In this case, at most, two sea blocks may exist.

(2-3) All of the surrounding blocks are land of the same area ([SAME]).The sub block of the case is shown in FIG. 8C.

(2-4) All of the surrounding blocks are land and land of one of theblocks belongs to different area of land of another land block([DIFFER]). The sub block of the case is shown in FIG. 8D.

(2-5) All of the surrounding blocks are the sea ([SEA]). The sub blockof the case is shown in FIG. 8E.

Then, description is made about the further categorization of thecategory (3).

The category (3) is still categorized into categories (3-1) to (3-6).

(3-1) Sub block covers a sea block and a land block ([SEA_SIDE]). Thesub block in the case is shown in FIG. 9A.

(3-2) A land block is separated from another land block of another areaby the sea ([B_SEA]). The sub block in the case is shown in FIG. 9B. Asdescribed above, one area is normally separated from the other areas andwhen user of the game finishes (clears) a partial scenario, the areasare connected (or means of the connection is given). In this case, thesea separates one area from the other are.

(3-3) A land block is separated from another land block of another areaby a mountain ([HIMT]). The sub block in the case is also shown in FIG.9B. The areas are separated because of the same reason as the abovecategory (3-2).

(3-4) A land block is separate from another land block of another areaby a river ([B_RIVER]). The sub block in the case is shown in FIG. 9B.The areas are separated because of the same reason as the above category(3-2).

(3-5) Sub block covers land blocks of the same area ([B_lNT]). The subblock in the case is shown in FIG. 9C.

(3-6) Sub block covers sea blocks ([SEA]). The sub block in the case isshown in FIG. 9D.

next, description is made about expansion process and wearing process inmore detail. By performing the process described above, for example,actual seaside (boundary between the land blocks and the sea blocks) hasbeen created as shown in FIG. 6. Configuration of the actual seasiderelates to blocks belong to the above categories [SEA_SAME],[SEA_DIFFER], [SEA_SIDE], and [B_SEA]. Therefore, the expansion processand the wearing process are performed about these categories of blocks.

Expansion Process

Description is made about the process with reference to FIGS. 10 and 11.As described about FIG. 5, projected portion such as a cape may beprojected only within the predetermined sub block range. For example, inFIG. 10A, the top left seaside of the land block can be projected orworn in a range of a sub block which covers four blocks (the sub blockbelongs to [SEA_SAME]). This is because that the middle additional pointpt is randomly located in the sub block.

Herein, to create more complex geographical features to express morenatural seaside, the seaside is expanded so as not to connect the otherland block. In this example, process about a sub block is illustrated,but process about a sub block is similar to the process about the subblock [SEA_SAME].

The sub block [SEA_SAME] is categorized into three patterns as shown inFIGS. 10B, 11A, and 11B, according to on the number of land blocks andthe number of sea blocks.

In FIG. 10B, a sub block A which covers a sea block and two sub blocks Eand B ([SEA_SIDE]) are shown. In FIG. 11A, a sub block A which coverstwo sea blocks, two sub blocks E and D ([SEA_SIDE]), and a sub block B([SEA]) are shown. In FIG. 11B, a sub block A which covers three seablocks, two sub blocks C and D ([SEA_SIDE]), and two sub blocks B and E([SEA]) are shown.

In FIGS. 10B, 11A, and 11B, each of pt0 and pt1 represents the point “2”used in the first tranformation (denoted by ), and pt4 represents middleadditional point used in the first transformation (denoted by “▴”). Inthe first transformation, pt4 is connected to pt0 and pt1 to createseaside. Also, pt4 is not used and pt0 and pt1 may be connected eachother.

Herein, a new points pt2 is added to each example shown in FIGS. 10B,11A, and 11B, and a new point pt3 is added to the example shown in FIG.11B. In FIG. 10B, x-coordinates of the pt0, pt1, and pt4 are averagedand y-coordinates of the pt0, pt1, and pt4 are averaged, and the pt2 isadded at the location having the averaged x-coordinate and the averagedy-coordinate. Therefore, if when x-coordinate and y-coordinate of apoint ptn can be represented as (Xn, Yn) on the basis of an arbitrarypoint on the field map, coordinates of pt0, pt1, and pt4 can berepresented as (x0, y0), (x1, y1), and (x4, y4), respectively. Further,coordinates of pt2 is represented as ((x0+x1+x4)/3,(y0+y1+y4)/3).

Herein, one of a triangle connecting points pt0, pt2, and pt4 and atriangle connecting points pt1, pt2, and pt4 is selected as land toexpand a land portion. The both triangles may be selected. The selectionof triangles may be performed using a random number. Therefore, if onlythe triangle which connects points pt0, pt2, and pt4 is selected, theseaside is formed along points pt0, pt2, pt4, and pt1. On the otherhand, if only the triangle which connects points pt1, pt2, and pt4 isselected, the seaside is formed along points pt0, pt4, pt2, and pt1.

In FIG. 11A, a point pt2 is randomly located in a sub block B. Herein,one of a triangle connecting points pt0, pt2, and pt4 and a triangleconnecting points pt1, pt2, and pt4 is selected as land to expand a landportion. The both triangles may be selected.

In FIG. 11B, each of points pt2 and pt3 is randomly located in a subblock B. Herein, one of a triangle connecting points pt0, pt2, and pt4and a triangle connecting points pt1, pt3, and pt4 is selected as landto expand a land portion. The both triangles may be selected. Therefore,if only the triangle which connects points pt0, pt2, and pt4 isselected, the seaside is formed along points pt0, pt2, pt4, and pt1. Onthe other hand, if only the triangle which connects points pt1, pt3, andpt4 is selected, the seaside is formed along points pt0, pt4, pt3, andpt1. If the both triangles are selected, the seaside is formed alongpoints pt0, pt2, pt4, pt3, and pt1.

The above mentioned expansion process can transform the seaside morecomplex to create more natural seaside by projecting the seaside towardthe sea.

Wearing Process

The wearing process selects some land cells (cells belong to the landportion) contacting with a sea cell (cell belongs to the sea portion)among sub blocks [SEA_SAME], [SEA_DIFFER], [SEA_SIDE], and [B_SEA],creates line starting from one of the land cells in the land portionwith random curve, and changes two cells wide land cells to sea cellsalong the created line. As described above, the cell means aquadrilateral which is obtained by dividing the whole field map into 128by 128 in a lattice form. When the cell is assigned to the sea, the cellis referred to as “sea cell”, when the cell is assigned to land, thecell is referred to as “land cell”.

In this example, description is made about a sub block [SEA_SAME] withreference to FIG. 12, other blocks [SEA_DIFFER], [SEA_SIDE], and [B_SEA]may be processed in a similar manner.

In FIG. 12A, a sub block [SEA_SAME] and an adjacent block is shown. Asdescribed above, a sub block includes 8 by 8 cells. At first, a sea cellwhich contacts with a land cell is selected. Then, line is extended withrandomly curving from a land cell contacting with the selected sea celltoward land. The extension of the line is performed by some extensionoperations. The direction and length of each extension operation aredetermined, for example, by a random number. After repeating theextension operations, a wearing line is created as shown in FIG. 12.

When the wearing line is created, cells are worn along the line with twocells width. That is, the worn cells (land cells) are changed to seacells. The operation is shown in FIG. 12B. Herein, cells which arechanged to sea cells are denoted by x mark. Also, a way of treating oftwo cells width is decided as desired. For example, in FIG. 12B, wearingline cells which the wearing line passes through and upper, lower,right, and left adjacent cells of the wearing line cells are changed tosea cells. As shown in FIG. 12B, the wearing line can proceed beyond theboundary between the sub blocks, but can not stride the path between thepoints established at step S24. This is because that the path should belocated on land, and for each cell, information whether or not the cellis assigned to the path is managed.

Also, it is possible to give a various limitation of location where thewearing line is expanded to (that is, length of the wearing line). Thewearing process may be further repeated by selecting some starting landcells.

In FIG. 13, field map processed by the processes mentioned above isshown. The boundary between a land portion and a sea portion, that isseaside, has various and complex undulations to form more naturalgeographical features comparing with the seaside shown in FIG. 6. Also,the seaside in FIG. 13 is drastically transformed far from the originalquadrilateral blocks.

Returning to flowchart in FIG. 2, in step S28, land which is processedby the second transformation is decorated. The decoration processincludes 3D process, scene arrange process, and object arrange process.

The 3D process adds 3D effect on the field map to express more naturaland undulating land. The scene arrange process arranges a snowy fieldand a desert according to setting of each area. The object arrangeprocess arranges objects and items required for the game on the fieldmap.

These processes are previously or dynamically (with an advance of thegame) performed. Furthermore, the scene arrange process arranges foreston a grassy field or a snowy field, and arranges a craggy mountain on adesert. The size and location of the forest and the craggy mountain maybe determined on the basis of a random number. In this example, since itis necessary that the areas are conceptually separated each otherbecause of configuration of the game, geographical items which preventsa character from pass through, such as a mountain, a river, and a lake,are located at the boundaries between areas.

Furthermore, since it should be possible to move all the blocks in anarea, for example when a sub block is isolated by the sea or a river, abridge should be located, or when a sub block is separated by amountain, a tunnel is created in the mountain. Also, the bridge and thetunnel are created so as to connects two points “2”.

Example of field map which is obtained by performing these processes isshown in FIG. 13. A shape of land portions is drastically changed, buteach of the portions still corresponds to one of the sub area shown inFIG. 3. Therefore, description is made about each part of the field mapusing the names of the sub areas.

In the example shown in FIG. 13, since sub areas b0 and a0 are assignedto showy field and sub areas c0 and c2 are assigned to desert, snowyfield (shown in FIG. 13 as a field shadowed by vertical lines) is shownin the sub areas b0 and a0, and desert (shown in FIG. 13 as a fieldshadowed by horizontal lines) is shown in the sub areas c0 and c2.

Mountains (shown in FIG. 13 as fields shadowed by slanted lines) arelocated at boundaries between the sub areas b1 and b0, b0 and a0, a0 anda1, c0 and c1, c1 and d0, and d0 and d1. And if the above two sub areasbelong to the same area, a tunnel (shown in FIG. 13 as a symbol denotedby two short lines crossing the mountain) is located to pass through themountain.

Rivers (the mouths of the rivers are denoted by arrows in FIG. 13) arelocated at boundaries between the sub areas a0 and a1, c0 and c1, and d0and d1. Since the pairs of the sub areas belong to the same area,bridges (shown in FIG. 13 as symbols denoted by two short lines crossingthe rivers) are built so that the game character may passes through therivers.

Three pairs of sub areas a2 and a0, a1 and a3, and c2 and c0 are eachseparated by the sea, since one of the pair is island. But, since thepairs are each belong to the same area, bridges (shown in FIG. 13 assymbols denoted by two short lines crossing the sea) are built so thatthe game character may passes through the sea.

The remaining portions of land are grassy field, and forests (shown inFIG. 13 as fields filled by a plurality of dots) are located in someparts of the grassy field. Also, craggy mountains (not shown in FIG. 13)are randomly located in desert portions. Furthermore, a lake (shown inFIG. 13 as a field filled by a plurality of x marks) is located in thesub area a0.

In the real game, thus generated field map is displayed as a bird's-eyeview, or partly enlarged and displayed in a three-dimensional way as astage of the game using information of the field map.

Explanation has been made about the illustrative field map, but it isobvious that the transformation process of the invention can be appliedto a various field maps. Further, detail settings of the invention arenot limited to the above example, and may be optionally selected. Thesettings include, for example, the number of blocks, the number ofcells, the number of areas, assigning of a sub area, and an arrangingway of a snowy field.

According to the invention, a method is provided which automaticallychanges information of a field map expressing a dungeon to represent thedungeon in more natural aspect and with more complex geographicalfeatures.

What is claimed is:
 1. A method of generating a field map used in avideo game, comprising the steps of: dividing the field map whichconsists of a plurality of blocks, into a first zone and a second zoneby a boundary including sides and corners of the blocks; determining afirst point for each side of the boundary on the basis of a location ofeach side of the boundary; determining a second point for each corner ofthe boundary on the basis of a location of each corner of the boundary;and transforming the boundary by connecting the first points and thesecond points.
 2. A method of generating a field map used in a videogame, comprising the steps of: dividing the field map into a pluralityof quadrilateral blocks; assigning each of the divided blocks to eithera first zone or a second zone; selecting sides, each of which forms apart of a boundary between the first zone and the second zone, fromsides of the blocks; selecting a point which corresponds to a corner ofone of the blocks and which is included in the boundary; determining afirst point for each selected side on the basis of a location of eachside of the boundary; determining a second point for each selected pointon the basis of a location of each corner of the boundary; andtransforming the boundary by connecting the first points and the secondpoints.
 3. The method of claim 2 further comprising the steps of:selecting two first points, each of which corresponds to a side, the twocorresponding sides are adjacent to each other; selecting one secondpoint which corresponds to a corner formed by the two correspondingside; determining a third point by moving the selected second point onthe basis of an aspect of the assigning of the divided blocks to thefirst zone or the second zone; and transforming the boundary byconnecting the two selected first points and a point which is optionallyselected from the selected second point and the determined third point.4. The method of claim 3, wherein each block in the first zone belongsto an area, the determination of the third point is performed based on,considering blocks including two columns and two rows, either of (a) thenumber of the blocks which belong to the first zone, (b) whether theblocks which belong to the first zone belong to different areas or not,and (c) location relationship, when there is at least one block whichbelongs to the second zone, between the blocks which belong to the firstzone and the at least one block which belongs to the second zone.
 5. Amethod of generating a field map used in a video game, comprising thesteps of: dividing the field map into a plurality of quadrilateralcells; assigning each of the divided cells to either a first zone or asecond zone; determining a first cell which belongs to the first zoneand is next to a cell which belongs to the second zone; selecting a cellwhich belongs to the first zone and is next to the first cell, andfurther repeatedly selecting a cell which belongs to the first zone andis next to the selected cell; and transforming a boundary between thefirst zone and the second zone by changing cells having a predeterminedlocation relationship to the selected cells to cells which belong to thesecond zone.
 6. The method of claim 5, wherein the cells having thepredetermined location relationship include the selected cells, firstadditional cells located on the same column as the selected cells and ona upper row nearest to the selected cells, second additional cellslocated on a right column nearest to the selected cells, and thirdadditional cells located on the upper row nearest to the secondadditional cells.
 7. The method of claim 5, wherein the selecting steprandomly selects, as adjacent cell, one of cells located on the upperrow, the lower row, the right column, and the left column, all of whichare nearest to a previous cell, and repeats the random selectionpredetermined times.
 8. A method of generating a field map used in avideo game, comprising the steps of: dividing the field map into aplurality of quadrilateral blocks including a plurality of quadrilateralcells; assigning each of the divided blocks to either a first zone or asecond zone; selecting sides, each of which forms a part of a boundarybetween the first zone and the second zone, from sides of the blocks;selecting a point which corresponds to a corner of one of the blocks andwhich is included in the boundary; determining a first point for eachselected side on the basis of a location of each side of the boundary;determining a second point for each selected point on the basis of alocation of each corner of the boundary; selecting two first points,each of which corresponds to a side, the two corresponding sides areadjacent to each other; selecting one second point which corresponds toa corner formed by the two corresponding side; determining a third pointby moving the selected second point on the basis of an aspect of theassigning of the divided blocks to the first zone or the second zone;transforming the boundary by connecting the two selected first pointsand a point which is optionally selected from the selected second pointand the determined third point; selecting a first cell which belongs tothe first zone and is next to a cell which belongs to the second zone;selecting a cell which belongs to the first zone and is next to thefirst cell, further selecting a cell which belongs to the first zone andis next to the selected cell, and repeating the selection of a cell; andtransforming the transformed boundary by changing cells having apredetermined location relationship to the selected cells to cells whichbelong to the second zone.
 9. A video game system which generates afield map comprising: block division means which divides the field mapinto a plurality of quadrilateral blocks; block assign means whichassigns each of the divided blocks to either a first zone or a secondzone; side select means which selects sides each of which forms a partof a boundary between the first zone and the second zone, from sides ofthe blocks; corner select means which selects a point which correspondsto a corner of one of the blocks and which is included in the boundary;first point determining means which determines a first point for eachselected side on the basis of a location of each side of the boundary;second point determining means which determines a second point for eachselected point on the basis of a location of each corner of theboundary; and first transforming means which transforms the boundary byconnecting the first points and the second points.
 10. The system ofclaim 9 further comprising: first point selecting means which selectstwo first points each of which corresponds to a side, the twocorresponding sides are adjacent to each other; second point selectingmeans which selects one second point which corresponds to a cornerformed by the two corresponding sides; third point determining meanswhich determines a third point by moving the selected second point onthe basis of an aspect of the assigning of the divided blocks to thefirst zone or the second zone by the block assign means; and secondtransforming means which transforms the boundary by connecting the twoselected first points and a point which is optionally selected from theselected second point and the determined third point.
 11. A video gamesystem which generates a field map comprising: cell dividing means whichdivides the field map into a plurality of quadrilateral cells; cellassign means which assigns each of the divided cells to either a firstzone or a second zone; first cell selecting means which selects a firstcell which belongs to the first zone and is next to a cell which belongsto the second zone; second cell selecting means which selects a cellwhich belongs to the first zone and is next to the first cell, furtherselecting a cell which belongs to the first zone and is next to theselected cell, and repeating the selection of a cell; and transformingmeans which transforms a boundary between the first zone and the secondzone by changing cells having a predetermined location relationship tothe selected cells to cells which belong to the second zone.
 12. A videogame system which generates a field map comprising: block division meanswhich divides the field map into a plurality of quadrilateral blocksincluding a plurality of quadrilateral cells; block assign means whichassigns each of the divided blocks to either a first zone or a secondzone; side select means which selects sides each of which forms a partof a boundary between the first zone and the second zone, from sides ofthe blocks; corner select means which selects a point which correspondsto a corner of one of the blocks and which is included in the boundary;first point determining means which determines a first point for eachselected side on the basis of a location of each side of the boundary;second point determining means which determines a second point for eachselected point on the basis of a location of each corner of theboundary; first point selecting means which selects two first pointseach of which corresponds to a side, the two corresponding sides areadjacent to each other; second point selecting means which selects onesecond point which corresponds to a corner formed by the twocorresponding sides third point determining means which determines athird point by moving the selected second point on the basis of anaspect of the assigning of the divided blocks to the first zone or thesecond zone by the block assign means; first transforming means whichtransforms the boundary by connecting the two selected first points anda point which is optionally selected from the selected second point andthe determined third point; first cell selecting means which selects afirst cell which belongs to the first zone and is next to a cell whichbelongs to the second zone; second cell selecting means which selects acell which belongs to the first zone and is next to the first cell,further selecting a cell which belongs to the first zone and is next tothe selected cell, and repeating the selection of a cell; and secondtransforming means which transforms the transformed boundary by changingcells having a predetermined location relationship to the selected cellsto cells which belong to the second zone.
 13. A recording mediumreadable by a computer, tangibly embodying a program of generating afield map used in a video game, comprising the steps of: dividing thefield map into a plurality of quadrilateral blocks; assigning each ofthe divided blocks to either a first zone or a second zone; selectingsides each of which forms a part of a boundary between the first zoneand the second zone, from sides of the blocks; selecting a point whichcorresponds to a corner of one of the blocks and which is included inthe boundary; determining a first point for each selected side on thebasis of a location of each side of the boundary; determining a secondpoint for each selected point on the basis of a location of each cornerof the boundary; and transforming the boundary by connecting the firstpoints and the second points.
 14. A recording medium readable by acomputer, tangibly embodying a program of generating a field map used ina video game, comprising the steps of: dividing the field map into aplurality of quadrilateral cells; assigning each of the divided cells toeither a first zone or a second zone; selecting a first cell whichbelongs to the first zone and is next to a cell which belongs to thesecond zone; selecting a cell which belongs to the first zone and isnext to the first cell, further selecting a cell which belongs to thefirst zone and is next to the selected cell, and repeating the selectionof a cell; and transforming a boundary between the first zone and thesecond zone by changing cells having a predetermined locationrelationship to the selected cells to cells which belong to the secondzone.
 15. A recording medium readable by a computer, tangibly embodyinga program of generating a field map used in a video game, comprising thesteps of: dividing the field map into a plurality of quadrilateralblocks including a plurality of quadrilateral cells; assigning each ofthe divided blocks to either a first zone or a second zone; selectingsides, each of which forms a part of a boundary between the first zoneand the second zone, from sides of the blocks; selecting a point whichcorresponds to a corner of one of the blocks and which is included inthe boundary; determining a first point for each selected side on thebasis of a location of each side of the boundary; determining a secondpoint for each selected point on the basis of a location of each cornerof the boundary; selecting two first points each of which corresponds toa side, the two corresponding sides are adjacent to each other;selecting one second point which corresponds to a corner formed by thetwo corresponding sides; determining a third point by moving theselected second point on the basis of an aspect of the assigning of thedivided blocks to the first zone or the second zone; transforming theboundary by connecting the two selected first points and a point whichis optionally selected from the selected second point and the determinedthird point; selecting a first cell which belongs to the first zone andis next to a cell which belongs to the second zone; selecting a cellwhich belongs to the first zone and is next to the first cell, furtherselecting a cell which belongs to the first zone and is next to theselected cell, and repeating the selection of a cell; and transformingthe transformed boundary by changing cells having a predeterminedlocation relationship to the selected cells to cells which belong to thesecond zone.